Receiving arrangement for radiosignals



Nov. 7, 19330 F: scHRoTER Ex AL RECEIVING" ARRANGEMENT FOR RADIOSIGNALS Filed Jan. 30, 1929 am o/z'h'er avweutozs FRITZ, SCHROETER WlLHELM RUNGE 331 Weir a'Wome %%Q Patented Nov. 7, 1933 PATENT FFICE RECEIVING ARRANGEMENT FOR. RADIOSIGNALS Fritz Schroter and Wilhelm. Runge, Berlin, Germany, assignors to Tel-efunken Gesellschaft fiir Drahtlose Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application January 30,

and in Germany 6 Claims.

The present invention relates to the reception of signals transmitted through space on short electromagnetic waves.

The invention, more particularly speaking, concerns an arrangement whereby the disturbances to the service caused by fading are diminished. This end is attained by diversity reception, that is, by the provision of several antennas or antenna systems having different fading characteristics, preferably by being mounted at comparatively great distance from one another, and of a special receiver circuit upon which the different antenna systems are brought to act. The said receiver circuit, according to our invention, consists of an A. C. circuit which is influenced by the impulses fed therein from the respective antenna systems, in such a way that an indicator or translating device which is connected with the A. C. circuit is rendered operative even when impulses are coming in from one of the antenna systems only, and the result is that the indicator outfit will record the signals when several of the other antenna systems fail to pick up signals owing to fading.

The single figure of the drawing illustrates the preferred embodiment of the invention.

Referring to the drawing, Al, A2, A3, are three antennas or antenna systems mounted apart from one another at distances which are not small compared with the working wave. The oscillations picked up by each one of these antennas are fed, preferably after amplification, to the respective rectifiers g1, g2, 93, the amplifiers being denoted by v1, v2, '03. Now, these rectified currents serve to act upon three thermionic tubes connected with an A. C. circuit fed from on A. C. generator E in such a manner that the intensity of the A. C. supplied from said genrator H is caused to vary at the rhythm of the ncoming signals in said A. C. circuit, with the 'esult that an indicator or recorder I, with the C. circuit, is thereby influenced, either director indirectly.

As can be seen from the diagram, the three thermionic tubes R1, R2, and R3 are connected in parallel with. the A. C. generator H, and at the grids of the said three tubes, D. O. potentials caused by the oscillations of each of the antenna systems are set up, which influence the conducting powers of the tubes. The regulation of the working potentials most suitably is so chosen that in a case where no oscillations are transmitted, the tube represents an infinitely high resistance, whereas, upon the arrival of signal waves, a biasing potential is set up at the grid 1929, Serial No. 336,038, February 13, 1928 such that the A. C. circuit is closed as a consequence. If the internal resistance w of the receiver apparatus I is relatively high compared with the internal resistances of the'tube used, the strength of the current flowing in the A. C. circuit will be nearly independent of whether all three tubes R1, R2, and R3 are simultaneously conducting or whether a positive grid potential is imparted from the incoming oscillations to say, only one of the tubes. Hence, this receiver circuit acts like a limiting means which is passed by a current of unvarying intensity regardless of how many of the antenna systems are excited. The rectifier means may be so chosen that no separate valves are provided, but that in the amplifier arrangement which amplifies the 17 energy coming from the respective antenna system, the last tube is designed to act as a rectifying amplifier.

Hence, the arrangement hereinbefore disclosed is suited for the recording of telegraphic signals and especially of pictures in black and white. By choosing a different adjustment of the value of the'tube biasing potentials, also a quantitative control of the A. C. in the pulsating-current cir- 8 cuit may be insured. It is, of course, important that the connecting or transfer lines K, which are likely to be of considerable length, should be so designed as regards length and balance that no disturbing reflections or interferences of the signals will be occasioned. For this reason, wherever necessary, recourse may be had to equalizing and phase-regulating means known from cable engineering.

It is important in the sense of this invention 9 that the frequency of the A. C. generated by generator H should not be chosen unduly'low, indeed, this frequency should be so chosen that the period of oscillation is small referred to the time-constants of the indicator or recorder apparatus. Under practical conditions, the frequency of the A. C. should probably be over 5000 cycles per second.

We claim:

7 1. The method of diversity reception which includes simultaneously making a plurality of energy collections of the same signal at the same wave length, but which have relatively difierent fading characteristics, separately rectifying each of the collected energies, utilizing each of the rectified energies to separately control the flow of locally generated alternating electrical energy, combining the resulting energies, and translating the combined energy.

2. The method of diversity reception which includes collecting radiated energy of the same wave length at a plurality of geographically spaced points, separately amplifying each of the collected energies, separately rectifying each oi the amplified energies, separately controlling the flow of locally generated alternating electrical energy in accordance with each of the rectified energies, combining the resulting energies, and

translating the combined energy.

3. A diversity receiving system comprising a plurality of geographically separated antennas, each antenna being adapted to respond to the same Wave length of the transmitted signal, a rectifier coupled to each of the antennas, a local source of alternating electrical energy, separate means to control the flow of the locally generated electrical energy in response to each of the rectified energies, means to combine the resulting energies, and means to translate the combined electrical energy.

4. A diversity receiving system comprising a plurality of' geographically separated antennas, each adapted to respond to the same wave length of the transmitted signal, a detector coupled to each of the antennas, a plurality of electron emission tubes each having a control electrode socoupled to one of the rectifiers that the tube is made conductive upon reception of signal energy, a translating device, and a source of alternating electrical energy coupled to each of the tubes and to the translating device, so that the translating device is responsive to the combined energy controlled by all of the antennas. 5. A diversity receiving system comprising a plurality of geographically spaced antennas, each antenna being adapted to respond to the same wave length of the transmitted signal, an amplifier coupled to each of the antennas, a rectifier coupled to each of the amplifiers, an electron emission tube coupled to each of the rectifiers, said tubes each having a control electrode so coupled to the rectifier that the tubes are made conductive upon reception or" signal energy, a translating device, and a local alternating current generator coupled to the translating device and across the anode to cathode circuits of each of the tubes, so that the translating device is responsive to the combined signal controlled energy.

6. Arrangement for the reception of wireless signals, especially for picture and telegraphy Work, comprising a plurality of geographically spaced antenna systems mounted certain distances apart from one another, each antenna being adapted to' respond to the same wave length of the transmitted signal, separate rectifiers, and a common alternating current circuit so influenced that an indicator or recorder apparatus associated with this alternating current circuit rendered" operative by' the radio frequency oscillations of even only one of the antenna systems, the frequency of the alt ng current flowing in said alternating cur; eat circuit being chosen so high that its period of oscillation is small relative to the-timeconstant of the indicator apparatus.

- FRITZ SCI-IROTER. WILHELM RUNGE. 

